Another day, another round of airline earnings reports — and yet another notice from Standard & Poor’s that another airline is now on credit watch, with further rating downgrades a distinct possibility.

Allegiant Travel Company posted results late Tuesday while AirTran came flying in today. The one thing both airlines have in common? They both posted nice profits for the quarter.

Take these guys out and buy them a beer. They certainly deserve it.

Allegiant posted a profit of $23.8 million, up 801% from a year ago. The airline flies only MD-80s. I would have expected nothing less, considering the drop in the price of fuel.

But there is much more to the Allegiant story as those of you who hang out around here know. And in regard to their overall business model — which relies heavily on ancillary revenue — this quarter really didn’t disappoint as the airline saw its ancillary revenues per ASM increase 17%.

AirTran, which is currently running kind of a hybrid operation in terms of ancillary revenues and more demand based scheduling that has been so advantageous to Allegiant versus the more traditional legacy carrier business model turned in another good quarter today as well.

The airline posted a profit of $78.4 million or $0.56. This was a huge turnaround from last year, when the airline posted a loss of $14.8 million or $0.14.

Excluding unrealized derivative gains associated with the airline’s hedging activities, the airline posted a profit of $46.6 million or $0.34.

Interestingly, even here though, unlike at Allegiant, revenues were down. At Allegiant the airline saw operating revenues up 12.5%. on a 30.3% growth in ASMs no less.

AirTran posted a 12.9% drop in revenues. However, the airline also posted a whopping 27.3% drop in operating expenses. There is where the profit came from. ASMs here were down 7.6% for the quarter.

All said and done — a good quarter for both airlines. Especially considering the rest of the carnage we’ve seen reported from almost everybody else.

One late note that hit the wires after the close today. Standard and Poor’s said this afternoon that it had put UAL Corp., the parent of United Airlines on credit watch for a possible further downgrade.

The company’s S&P rating is already buried in the “junk” status, sitting at a “B -.”

S&P also warned that AMR, parent of American AIrlines is also now on the bad list as well, as it was also placed on the list for a potential downgrade. American currently is also rated “B -.”

We’ll look at the Delta Air Lines loss in another post.